ARE PEOPLE WITH SCHIZOPHRENIA DRAWN TO SMOKING POT?

A COMPOUND related to the active ingredient in marijuana may be
accumulating in the spinal fluid of people with schizophrenia. This
might explain why many sufferers smoke pot.

Many researchers blame schizophrenia on an overactive dopamine system
in the brain. Daniele Piomelli and colleagues at the University of
California at Irvine already knew that making rats' dopamine receptors
hyperactive caused a surge in anandamide, a lipid that binds to the
same receptors in the brain as marijuana.

Now Piomelli's group has examined cerebrospinal fluid from 10
schizophrenic patients, taken for diagnostic purposes at the Medical
College of Hannover in Germany. They found that fluid from
schizophrenic patients had on average twice as much anandamide as
fluid from people who didn't have schizophrenia (NeuroReport, vol 10,
p 1665).

One explanation for the higher levels in schizophrenics is that the
brain is attempting to compensate for a hyperactive dopamine system.
"It's the brain's response to bring this dopamine activity down," says
Piomelli. But the brain cannot keep the amount of anandamide high
enough to lower dopamine levels, he says.

This might also explain why schizophrenics often smoke marijuana. The
drug's active agent, THC, and anandamide both bind to the same
receptor, so patients might be treating themselves, he says. But
because pot does not act selectively in the brain, Piomelli does not
consider it a useful treatment for schizophrenia. "I don't think the
patient wants to be high," he says. "I think the patient wants to feel
better."

One weakness in the data so far is that five of the patients were taking
medication for their symptoms and three others vvere using marijuana daily.
The effects of these drugs on endogenous cannabinoid levels is not known.
"It is imperative to continue with a Sarger sample," says Piomelli. The
researchers are now testing fluid. from more patients to see if the
correlation still holds true.